/*
 *  RFC 1186/1320 compliant MD4 implementation
 *
 *  Based on XySSL: Copyright (C) 2006-2008  Christophe Devine
 *
 *  Copyright (C) 2009  Paul Bakker <polarssl_maintainer at polarssl dot org>
 *
 *  All rights reserved.
 *
 *  Redistribution and use in source and binary forms, with or without
 *  modification, are permitted provided that the following conditions
 *  are met:
 *
 *    * Redistributions of source code must retain the above copyright
 *      notice, this list of conditions and the following disclaimer.
 *    * Redistributions in binary form must reproduce the above copyright
 *      notice, this list of conditions and the following disclaimer in the
 *      documentation and/or other materials provided with the distribution.
 *    * Neither the names of PolarSSL or XySSL nor the names of its contributors
 *      may be used to endorse or promote products derived from this software
 *      without specific prior written permission.
 *
 *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 *  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 *  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 *  FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 *  OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 *  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
 *  TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 *  PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 *  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 *  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 *  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
/*
 *  The MD4 algorithm was designed by Ron Rivest in 1990.
 *
 *  http://www.ietf.org/rfc/rfc1186.txt
 *  http://www.ietf.org/rfc/rfc1320.txt
 */

#include "netif/ppp/ppp_opts.h"
#if PPP_SUPPORT && LWIP_INCLUDED_POLARSSL_MD4

#include "netif/ppp/polarssl/md4.h"

#include <string.h>

/*
 * 32-bit integer manipulation macros (little endian)
 */
#ifndef GET_ULONG_LE
#define GET_ULONG_LE(n, b, i)                                                                                                                             \
    {                                                                                                                                                     \
        (n) = ((unsigned long)(b)[(i)]) | ((unsigned long)(b)[(i) + 1] << 8) | ((unsigned long)(b)[(i) + 2] << 16) | ((unsigned long)(b)[(i) + 3] << 24); \
    }
#endif

#ifndef PUT_ULONG_LE
#define PUT_ULONG_LE(n, b, i)                      \
    {                                              \
        (b)[(i)] = (unsigned char)((n));           \
        (b)[(i) + 1] = (unsigned char)((n) >> 8);  \
        (b)[(i) + 2] = (unsigned char)((n) >> 16); \
        (b)[(i) + 3] = (unsigned char)((n) >> 24); \
    }
#endif

/*
 * MD4 context setup
 */
void md4_starts(md4_context *ctx)
{
    ctx->total[0] = 0;
    ctx->total[1] = 0;

    ctx->state[0] = 0x67452301;
    ctx->state[1] = 0xEFCDAB89;
    ctx->state[2] = 0x98BADCFE;
    ctx->state[3] = 0x10325476;
}

static void md4_process(md4_context *ctx, const unsigned char data[64])
{
    unsigned long X[16], A, B, C, D;

    GET_ULONG_LE(X[0], data, 0);
    GET_ULONG_LE(X[1], data, 4);
    GET_ULONG_LE(X[2], data, 8);
    GET_ULONG_LE(X[3], data, 12);
    GET_ULONG_LE(X[4], data, 16);
    GET_ULONG_LE(X[5], data, 20);
    GET_ULONG_LE(X[6], data, 24);
    GET_ULONG_LE(X[7], data, 28);
    GET_ULONG_LE(X[8], data, 32);
    GET_ULONG_LE(X[9], data, 36);
    GET_ULONG_LE(X[10], data, 40);
    GET_ULONG_LE(X[11], data, 44);
    GET_ULONG_LE(X[12], data, 48);
    GET_ULONG_LE(X[13], data, 52);
    GET_ULONG_LE(X[14], data, 56);
    GET_ULONG_LE(X[15], data, 60);

#define S(x, n) ((x << n) | ((x & 0xFFFFFFFF) >> (32 - n)))

    A = ctx->state[0];
    B = ctx->state[1];
    C = ctx->state[2];
    D = ctx->state[3];

#define F(x, y, z) ((x & y) | ((~x) & z))
#define P(a, b, c, d, x, s)  \
    {                        \
        a += F(b, c, d) + x; \
        a = S(a, s);         \
    }

    P(A, B, C, D, X[0], 3);
    P(D, A, B, C, X[1], 7);
    P(C, D, A, B, X[2], 11);
    P(B, C, D, A, X[3], 19);
    P(A, B, C, D, X[4], 3);
    P(D, A, B, C, X[5], 7);
    P(C, D, A, B, X[6], 11);
    P(B, C, D, A, X[7], 19);
    P(A, B, C, D, X[8], 3);
    P(D, A, B, C, X[9], 7);
    P(C, D, A, B, X[10], 11);
    P(B, C, D, A, X[11], 19);
    P(A, B, C, D, X[12], 3);
    P(D, A, B, C, X[13], 7);
    P(C, D, A, B, X[14], 11);
    P(B, C, D, A, X[15], 19);

#undef P
#undef F

#define F(x, y, z) ((x & y) | (x & z) | (y & z))
#define P(a, b, c, d, x, s)               \
    {                                     \
        a += F(b, c, d) + x + 0x5A827999; \
        a = S(a, s);                      \
    }

    P(A, B, C, D, X[0], 3);
    P(D, A, B, C, X[4], 5);
    P(C, D, A, B, X[8], 9);
    P(B, C, D, A, X[12], 13);
    P(A, B, C, D, X[1], 3);
    P(D, A, B, C, X[5], 5);
    P(C, D, A, B, X[9], 9);
    P(B, C, D, A, X[13], 13);
    P(A, B, C, D, X[2], 3);
    P(D, A, B, C, X[6], 5);
    P(C, D, A, B, X[10], 9);
    P(B, C, D, A, X[14], 13);
    P(A, B, C, D, X[3], 3);
    P(D, A, B, C, X[7], 5);
    P(C, D, A, B, X[11], 9);
    P(B, C, D, A, X[15], 13);

#undef P
#undef F

#define F(x, y, z) (x ^ y ^ z)
#define P(a, b, c, d, x, s)               \
    {                                     \
        a += F(b, c, d) + x + 0x6ED9EBA1; \
        a = S(a, s);                      \
    }

    P(A, B, C, D, X[0], 3);
    P(D, A, B, C, X[8], 9);
    P(C, D, A, B, X[4], 11);
    P(B, C, D, A, X[12], 15);
    P(A, B, C, D, X[2], 3);
    P(D, A, B, C, X[10], 9);
    P(C, D, A, B, X[6], 11);
    P(B, C, D, A, X[14], 15);
    P(A, B, C, D, X[1], 3);
    P(D, A, B, C, X[9], 9);
    P(C, D, A, B, X[5], 11);
    P(B, C, D, A, X[13], 15);
    P(A, B, C, D, X[3], 3);
    P(D, A, B, C, X[11], 9);
    P(C, D, A, B, X[7], 11);
    P(B, C, D, A, X[15], 15);

#undef F
#undef P

    ctx->state[0] += A;
    ctx->state[1] += B;
    ctx->state[2] += C;
    ctx->state[3] += D;
}

/*
 * MD4 process buffer
 */
void md4_update(md4_context *ctx, const unsigned char *input, int ilen)
{
    int fill;
    unsigned long left;

    if (ilen <= 0) {
        return;
    }

    left = ctx->total[0] & 0x3F;
    fill = 64 - left;

    ctx->total[0] += ilen;
    ctx->total[0] &= 0xFFFFFFFF;

    if (ctx->total[0] < (unsigned long)ilen) {
        ctx->total[1]++;
    }

    if (left && ilen >= fill) {
        MEMCPY((void *)(ctx->buffer + left),
               input, fill);
        md4_process(ctx, ctx->buffer);
        input += fill;
        ilen -= fill;
        left = 0;
    }

    while (ilen >= 64) {
        md4_process(ctx, input);
        input += 64;
        ilen -= 64;
    }

    if (ilen > 0) {
        MEMCPY((void *)(ctx->buffer + left),
               input, ilen);
    }
}

static const unsigned char md4_padding[64] = {
    0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
};

/*
 * MD4 final digest
 */
void md4_finish(md4_context *ctx, unsigned char output[16])
{
    unsigned long last, padn;
    unsigned long high, low;
    unsigned char msglen[8];

    high = (ctx->total[0] >> 29) | (ctx->total[1] << 3);
    low = (ctx->total[0] << 3);

    PUT_ULONG_LE(low, msglen, 0);
    PUT_ULONG_LE(high, msglen, 4);

    last = ctx->total[0] & 0x3F;
    padn = (last < 56) ? (56 - last) : (120 - last);

    md4_update(ctx, md4_padding, padn);
    md4_update(ctx, msglen, 8);

    PUT_ULONG_LE(ctx->state[0], output, 0);
    PUT_ULONG_LE(ctx->state[1], output, 4);
    PUT_ULONG_LE(ctx->state[2], output, 8);
    PUT_ULONG_LE(ctx->state[3], output, 12);
}

/*
 * output = MD4( input buffer )
 */
void md4(unsigned char *input, int ilen, unsigned char output[16])
{
    md4_context ctx;

    md4_starts(&ctx);
    md4_update(&ctx, input, ilen);
    md4_finish(&ctx, output);
}

#endif /* PPP_SUPPORT && LWIP_INCLUDED_POLARSSL_MD4 */
